Riggs, E.S. 1935. A skeleton of Astrapotherium. Field Museum of Natural History, Geological Series 6(13):167-177. 1935. A skeleton of Astrapotherium. Field Museum of Natural History, Geological Series 6(13):167-177.
Riggs, E.S. 1935. A skeleton of Astrapotherium. Field Museum of Natural History, Geological Series 6(13):167-177. 1935. A skeleton of Astrapotherium. Field Museum of Natural History, Geological Series 6(13):167-177.